At optical frequencies or at other portions of the electromagnetic spectrum, reflectors such as mirrors are used to redirect light or other emissions. In many areas of application, high stiffness, light weight and/or minimum mass, is required, such as for example in space based applications, high frequency dynamic applications, etc. Some current designs for high stiffness-to-mass ratio mirrors include mirrors with stiffening ribs on the back side, mirrors with random cell structure foam attached to the backside, and mirrors with complete or incomplete face sheets attached to the other side of the stiffening ribs or random cell structure foam. In some current designs, low mass is achieved by making the structures using materials with physical properties favorable for mirror production. This includes mirror structures made from silicon carbide, beryllium, glass-ceramic such as ZERODUR™, silica, and glass such as PYREX™. Current designs also included combinations of the above techniques, such as for example beryllium mirrors with stiffening ribs, or silicon carbide mirrors with silicon carbide random cell foam.
There are drawbacks, however, with current designs. For example, beryllium mirrors with stiffening ribs can be difficult to fabricate. Moreover, beryllium is a toxic substance known to lead to health problems with either short-term or long-term exposure. In addition, fabrication with beryllium is difficult. Beryllium welding without filler material is limited to thin foils, requiring that high-purity, high-performance beryllium components be machined. For example, creating a high performance mirror from a sandwich panel structure consisting of two face sheets separated by a core can be difficult when starting with solid beryllium. Manufactures of beryllium mirrors must settle for designs with stiffening ribs, which yield lower stiffness-to-mass ratios than sandwich panel designs.
Although US Patent applications 2004/0136101A1 and 2006/0181794A1, both entitled OPEN LATTICE MIRROR STRUCTURE AND METHOD OF MAKING SAME, discuss mirrors with trusses, the size and construction limits the stiffness-to-mass ratio, which limits fidelity and high frequency operation.
Therefore, it is desirable to provide optical components that are lightweight, highly durable, hard materials, and can withstand a high temperature, oxidizing environment, and are easier to fabricate. Furthermore, it would be advantageous to use the minimum amount of material so that large-scale structures can be fabricated and fielded using a minimum of resources.